The present invention relates to a rolling bolster system.
With machines such as presses, forming tools such as the dies that are used therein, must be replaced from time to time for maintenance purposes or to produce different parts with the machine. Replacement of a die results in lost time because the press must be shut down while the die is being changed. Die changes can occur relatively frequently in manufacturing facilities. Die changes occur even more frequently at prototype facilities where parts are produced in relatively small lots. Therefore, in order to maintain press productivity it is essential that die changes occur rapidly.
It is conventional to equip presses with rolling bolsters to facilitate die changing. A rolling bolster is a mechanism that allows the press platen or "bolster" to move into and out of the press. When the bolster is out of the press, removal and replacement of the die is simplified.
One of the complications involved in rolling the bolster of a press that is so equipped, is the fact that in a press with cushion action, pins typically extend between the die and the cushion through the press bed and the bolster. The pins prevent movement of the bolster when they are in place.
The cushion pins provide a secondary action to the die which is mounted on the bolster. The pins engage mating sections of the die, providing secondary movement thereto in addition to the normal primary closing movement of the press. The pin driven secondary action of a particular die is generally unique to the part produced therein. Therefore, placement of the pins in the bolster varies according to the die mounted thereon.
The bottom of the pins typically engage a cushion located in the bed of the press. The cushion's slide mechanism generally provides movement to the pins pushing them through the bolster to engage the die. Conventionally, the bottom of the pin remains in contact with the slide mechanism due to the force of gravity.
Because the pins extend through the bed of the press and through the bolster, rolling the bolster out of the press conventionally requires the removal of the pins. Depending on the application, numerous pins are typically involved. Therefore, movement and replacement of the pins increases press down time. This is because the pins are relatively heavy and must be manually removed from within the press after the die has been removed and before the bolster can be rolled out.